<template>
  <div id="app">
    <div>
      <p>请选择你要购买的书籍</p>
      <ul v-for="item in arr" :key="item.name">
        <li>
          {{ item.name }}
          <button @click="item.count++">买书</button>
        </li>
      </ul>
      <table border="1" width="500" cellspacing="0">
        <tr>
          <th>序号</th>
          <th>书名</th>
          <th>单价</th>
          <th>数量</th>
          <th>合计</th>
        </tr>
        <tr v-for="(item, index) in arr" :key="item.name">
          <td>{{ index + 1 }}</td>
          <td>{{ item.name }}</td>
          <td>{{ item.price }}</td>
          <td>{{ item.count }}</td>
          <td>{{sum(item.price,item.count)}} </td>
        </tr>
      </table>
      <p>总价格为:{{ totalPrice }}</p>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      arr: [
        {
          name: "水浒传",
          price: 107,
          count: 0,
        },
        {
          name: "西游记",
          price: 192,
          count: 0,
        },
        {
          name: "三国演义",
          price: 219,
          count: 0,
        },
        {
          name: "红楼梦",
          price: 178,
          count: 0,
        },
      ],
    };
  },
  methods:{
    sum(price,count){
      return price* count
    }
  },
  computed: {
    totalPrice(){
      let total =0;
      for(let a  of this.arr){
        total+= a.price *a.count;
      }
      return total;

    }
  },
};
</script>

<style>
</style>